Caster pintle



May 1.0, 1966 E. H. scHuLTz, JR 3,249,960

CASTER PINTLE Filed Jan. e 1965 United States Patent O 3,249,960 CASTER PINTLE vEdward H. Schultz, Jr., Glencoe, Ill., assignor to Nagel- This invention relates generally to the art of casters and more particularly to casters which employ a tubular pintle.

Although solid metal pintles have been employed for many years in making casters, the advantages of a tubular pintle have been recently realized. The releasable retention of a caster in the structure that it supports is also commonly recognized; and in the case of solid pintles, radially resilient split rings have been frequently employed to grip' a surrounding socket while being axially restrained with respect to the pintle by an annular groove cut into the material of the pintle. The wall thickness of a tubular pintle, if kept within economical limits, however, precludes the `cutting of such a groove without seriously weakening the structure. In addition, rotary swa'ging, if practiced carefully enough to avoid distorting a tubular pintle, has proved to be excessively expensive. Therefore, the releasable retention of tubular pintle has heretofore been achieved by special socket structures.

Accordingly, an important .object of the present invention is to provide an economically produced caster pintle of annularly grooved, tubular construction.

Another object of the invention is to provide a tubular' caster pintle which is constructed to cooperate with a simple, Vstraight-walled socket.

Still another object of the inventionis to provide a caster pintle of tubular construction which is locally strengthened at an annular, spring member-receiving groove.

A more general object of the invention is to provide a new and improved caster arrangement.

A further object of the invention is -to provide a novel method of forming an annular groove Vin a tubular, caster pintle.

These and other objects and features of the invention will become more apparent from a consideration ofthe following descriptions.

A structure in accord with `the invention includes a rollable suppor-t arrangement comprising a frame mem- -ber having a substantially horizontal platform and floorengaging roller means. A hollow tubular pintle is secured to the frame member in upstanding relationship, and the pintle is formed with an annular constricted portion defining a receiving groove for an annular spring member. The tubular pintle 'is provided with straight-walled portions on opposite axial sides of the constricted portion; and in compliance with one aspect of the invention, the walls of the constricted portion are made thicker v than the straight-walled portions so that the constricted pintle, FIG. 2 being taken substantially along the line portion may successfully resist forces transmitted thereto by a spring member situated in the groove.

In order that the principles of the invention may be readily understood, a single embodiment thereof, but to which the application is not to be restricted, is shown in the accompanying draw-ing wherein:

FIG, 1 is a `side elevational view of a caster arrangement constructed in compliance with the `invention and shown supporting one leg 'of a furniture piece, the leg of the furniture piece being illustrated in cross-section to reveal the socket unit and the pintle and cooperating spring member being shown in broken outline to illustrate further details;

FIG. 2 is an enlarged, vertical sectional View showing` the socket unit and the upper end of the caster yoke and 2 2 of FIG. 1;

FIG. 3 is a top plan View in cross-section taken substantially along the line 3-.-3 of FIG. 2; and

FIG. 4 is a schematic View illustrating the method of making the annular groove and the tubular pintle incorporated in the caster arrangement of FIGS. 1-3.

Referring now in detail to the drawing, specifically to FIGS. 1 and 2, a caster arrangement indicated generally by the numeral 10 will be seen disposed for supporting one leg 12 of a furniture piece. Alternatively, the caster arrangement 10 may be used to support au appliance or' other structure which yit is desired' to move from place to place with facility. The caster arrangement 10 includes a rollable support arrangement 14, a hollow tubular pintle 16 and a tubular socket 18.

The support arrangement 14 comprises a yoke or frame member 20 having a substantially horizontal platform 22 and a pair of spaced arms 24 depending from the platform 22. Completing the support arrangement 14 is a floor-engaging wheel 26 which is journaled between the arms 24 by a shaft 28. The tubular pintle 16 is intended to be secured to the frame member 2 0 in upstanding relationship; and for this purpose, the platform 22 of the frame member is perforated with an aperture 30 illustrated in FIG. 2. Advantageously, the aperture 30 is formed in an upwardly deflected panel 32.

With particular reference to FIG. 2, the pintle 16 is seen to be fashioned as a hollow tube having a spherical closed upper end 34 and an open lower end- 36. The lower end 36 penetrates the aperture 30 in frame member 20; and in compliance with the invention, confronting shoulders are provided on the pintle for confining the panel 32 therebetween in mounting the pintle to the platform of the frame member. Specifically, the pintle 16 is fashioned with a doubled over or folded, radially outwardly extending portion 38 adjacent the lower end 36, this doubled over portion forming a shoulder that contacts the upper surface of panel 32. Cooperatively, the extreme edge of the lower end 36 of the pintle is headed or provided with a radially outwardly extending flange 40 which defines the confronting shoulder andwhich engages the lower surface of the panel 32, compressibly urging' the panel aga-inst the shoulder defined by the doubled over portion 38. It is recognized that the pintle 16 may be mounted to the frame member 20 by a ball bearing arrangement if desired.

In compliance with an important feature of the invention, the tubular pintle 16 is fashioned with an annular constricted port-ion 42 that defines a receiving groove for an annular lspring member 44. The pintle 16 is also provided with straight wall portions 46 and 48 on respective opposite axial sides of the constricted portion 42. The groove which is defined by the constricted portion 42 specifically comprises oppositely flaring sidewalls 50 and 52 and a root wall 54 that connects the sidewalls 50 and 52. In compliance with another important feature of the invention, the walls 50, 52 and 54 are made thicker than the straight wall portions 46 and 48 in order that the constricted portion 42 may effectively resist forces transmitted thereto by the spring member 44. This thicken-ing of the walls of -the constricted portion cooperates with the shaping of the groove defined by the constricted portion in generally trapezoidal section so as to form a'structure that is highlyresistant to deformation. The constricted portion 42 is advantageously situated in the upper half of the pintle where the spring 44 may serve to accept and distribute lateral thrust forces.

Continuing with reference to FIG. 2 and with secondary reference to FIG. 3, the spring menrber-44 is seen to takeA discontinuous annular shape. Specifically, the spring member is fashioned with a separation 56 and is fabricated from spring material. Thus, the member 44 may be resiliently expanded during assembly with the tubular pintle 16 while reacting resiliently to subsequent engagement with the inside of the tubular socket 18. More specifically, the spring mem-ber 44 is selected to have an inside diameter that is greater than the root diameter of the constricted portion 42, this inside diameter being at the same time less than the outside diameter of the straight wall portions 46 and 418. Accordingly, the spring member 44 is loosely retained in the groove. In addition, the outside diameter of the spring member 44 is selected to be greater than the outside diameter of the straight wall portions 46 and 48 whereby aggressively to engage the encompassing socket 18.

As is well shown in FIG. 2, the tubular socket 18 has an elongated, straight-walled body portion 58 which terminates at a curled bead `60 at its open, lower end and which terminates ata spherical, closed upper end 62. The spherical closed end 62 of the tubular socket 18 bearingly and rotatably receives the cooperatively shaped |upper end 34 of the pintle 16. It is important to recognize that the socket 18 is a simply constructed member devoid of special provisions for cooperating with the tubular pintle 16.

As has 'been described hereinabove, it is advantageous Ithat the vwalls of the constricted portion of the tubular pintle be provided in greater thickness than the remaining walls of that element. In compliance with the method aspects of the invention, these relative thicknesses are provided by .special procedures used in forming the constricted portion. Advantageously, the constricted portion in the tubular pintle is lformed by progressive punch press operations; and in FIG. 4, a closed end tubular element 64 is seen to have been partially formed with an annular groove 66. =In the nal formation of the groove, a pair of tools 68 and 70 having semi-circular notches 72 are urged radially into the partially formed groove 66 to draw the groove into nal shape. vSimultaneously, the pintle is struck an axial blow by a hammer 74. This combination of actions develops the desired thickening of the walls of the groove, forming an especially strong part resistant to deformation by the forces imposed thereon.

The manner in which the present invention may be practiced on the purposes to `which it may be put are evident from the foregoing descriptions.

The specific examples herein shown and described are to be considered as being primarily illustrative. Various changes in structure and procedure Will,.no doubt, occur to those skilled in the art; and such changes are to be understood as forming a part of this invention insofar as they fallwithin the spirit and scope off the appended claims.

'Ilhe invention is claimed as follows:

`1. In a caster arrangement, the combination comprising: a rollable support arrangement including a frame member; a hollow tubular pintle secured to said frame member in upstanding relationship, lsaid pintle having an annular constricted portion defining a receiving groove for a spring member and straight wall portions on opposite axial sides of said constricted portion, the walls of said constricted portion b-eing thicker than said straight wall portions whereby said constricted portion resists forces transmitted thereto by a spring mem-ber situated in said groove; and a radially resilient spring member in said groove.

2. lIn a caster arrangement, the combination comprising: a rollable support `arrangement including a frame member; a hollovv tubular pintle secured to said frame member in upstanding relationship, `said pintle having an annular constricted portion deining a receiving groove for a spring member and straight wall portions on opposite axial sides of said constricted portion, the walls of said constricted portion being thicker than said straight wal-1 portions whereby said constricted portion resists forces transmitted thereto by a spring member situated in said groove, said groove having oppositely Haring sidewalls and a root wall connecting said sidewalls whereby .to form a structure that is resistant to deformation; and a radially resilient spring member in said groove.

3. In a caster arrangement, the combination comprising: a rollable support arrangement including a frame member having an apertured, substantially horizontal platform and spaced arms depending from said platform, floor-engaging rotatable means, and means journaling said rotatable means to said arms; a hollow tubular pintle secured to said frame member in upstanding relationship, said pintle having `an annular constricted portion defining a receiving groove for a spring member and straight Wall portions on opposite axial sides of said constricted portion,l the walls of said constricted portion being thicker than said straight wall portions whereby `Said constricted portion resists forces transmitted thereto by a spring member situated in said groove, said pintle having a double over, radially outwardly extending portion adjacent its lower end, saiddoubled over portion forming -a shoulder in contact with the upper surface of said platform, thelower end of said pintle penetrating the aperture i'n said platform and having a headed extreme edge confronting said shoulder to mount said pintle to said platform; and a radially resilient spring member in said groove.

References Cited by the Examiner UNITED STATES PATENTS Re. 17,950 2/ 1931 Herold 16-38 548,825 10/ 1895 Clarke 16-38 `689,55 3 9/ 190I1 Livingstone 16-37 716,340 9/ 1902 Livingstone l 6-37 1,958,178 5/ 1934 Anderson 72-377 2,064,322 12/ 1936 Ruppert 7 2-37 7 JOSEPH D. SEERS, Primary Examiner.

ALBERT H. KAMPE, Examiner.

D. L. BURGESS, Assistant Examiner, 

1. IN A CASTER ARRANGEMENT, THE COMBINATION COMPRISING: A ROLLABLE SUPPORT ARRANGEMENT INCLUDING A FRAME MEMBER; A HOLLOW TUBULAR PINTLE SECURED TO SAID FRAME MEMBER IN UPSTANDING RELATIONSHIP, SAID PINTLE HAVING AN ANNULAR CONSTRICTED PORTION DEFINING A RECEIVING GROOVE FOR A SPRING MEMBER AND STRAIGHT WALL PORTIONS ON OPPOSITE AXIAL SIDES OF SAID CONSTRICTED PORITON, THE WALLS OF SAID CONSTRICTED PORTION BEING THICKER THAN SAID STRAIGHT WALL PORTIONS WHEREBY SAID CONSTRICTED PORTION RESISTS FORCES TRANSMITTED THERETO BY A SPRING MEMBER SITUATED IN SAID GROOVE; AND A RADIALLY RESILIENT SPRING MEMBER IN SAID GROOVE. 